[Elecraft] K3 S meter vs P3 S scale

[Alan Bloom]

The reason the P3 reads lower than the K3 on noise or SSB signals is
that each display point on the P3 screen covers only a small bandwidth.
As explained in the manual, each display point is about 1/450 of the
span.  For example, if the span is 45 kHz, then each display point only
covers about 100 Hz.

You'd see the same effect on the K3 if you narrowed the bandwidth from
2700 Hz to 100 Hz.  The S meter would read 10 * log (2700/100) = 14 dB
(2-3 S units) lower.

Alan N1AL


On Thu, 2011-05-05 at 21:59 -0600, Jim Miller KG0KP wrote:
> Seems to be quite a difference in the readings between the P3 showing S 
> scale and he S meter reading on the K3.  The software in both is up to 
> date(recently at least).  The difference is quite significant with the P3 
> being considerably lower.  Maybe I don't know how to read the two meters. 
> On the K3 I read the mostly steady peak reading excluding the static crashes 
> if any.  On the P3 using clear frequency noise as an example, I tend to read 
> the "average" of the noise trace.  Should I be reading the peaks 
> (disregarding static crashes)?
> 
> Is there a calibration I need to do?  To which and where is the procedure 
> spelled out?
> 
> Will I will need to order the new XG3? (please)
> 
> TIA, de Jim KG0KP 
> 
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>